The mammalian retinal ganglion cell population comprises a number of functionally distinct groups of neurons giving rise to a number of parallel information channels in the optic nerve which have proven to be of considerable importance in the organization of central visual pathways. Nevertheless, knowledge of the cellular interactions underlying the formation of these channels is largely incomplete. Furthermore, the retina is susceptible to damage from a variety of diseases and systemic disorders, most of which are poorly understood. Knowledge of how retinal neurons interact is essential for a complete understanding of how these diseases affect retinal tissue, and for the development of effective diagnostic as well as therapeutic procedures. This proposal is to do an intracellular analysis of the responses and receptive field properties of ganglion cells and other retinal neurons in the intact eye of the cat. Such as analysis will: (1) allow the synaptic inputs of functionally distinct types of ganglion cell to be identified; (2) allow the complex receptive field properties of non-spiking retinal neurons to be studied under natural optical conditions, and with the same stimuli used to study ganglion cell receptive fields; (3) allow a direct comparison to be made between the response properties of the ganglion cells and those of other retinal neurons to identical visual stimuli; (4) contribute to our understanding of the mechanisms and circuitry underlying the formation of the functionally distinct, parallel information channels which are a major organizational feature of the central visual pathways.